TY - JOUR
T1 - Behavior of Foodborne Pathogens <span class="named-content genus-species" id="named-content-1">Listeria monocytogenes</span> and <span class="named-content genus-species" id="named-content-2">Staphylococcus aureus</span> in Mixed-Species Biofilms Exposed to Biocides
JF - Applied and Environmental Microbiology
JO - Appl. Environ. Microbiol.
DO - 10.1128/AEM.02038-18
VL - 84
IS - 24
SP - e02038-18
AU - Oxaran, Virginie
AU - Dittmann, Karen Kiesbye
AU - Lee, Sarah H. I.
AU - Chaul, Luíza Toubas
AU - Fernandes de Oliveira, Carlos Augusto
AU - Corassin, Carlos Humberto
AU - Alves, Virgínia Farias
AU - De Martinis, Elaine Cristina Pereira
AU - Gram, Lone
A2 - Björkroth, Johanna
Y1 - 2018/12/15
UR - http://aem.asm.org/content/84/24/e02038-18.abstract
N2 - In nature and man-made environments, microorganisms reside in mixed-species biofilms, in which the growth and metabolism of an organism are different from these behaviors in single-species biofilms. Pathogenic microorganisms may be protected against adverse treatments in mixed-species biofilms, leading to health risk for humans. Here, we developed two mixed five-species biofilms that included one or the other of the foodborne pathogens Listeria monocytogenes and Staphylococcus aureus. The five species, including the pathogen, were isolated from a single food-processing environmental sample, thus mimicking the environmental community. In mature mixed five-species biofilms on stainless steel, the two pathogens remained at a constant level of ∼105 CFU/cm2. The mixed five-species biofilms as well as the pathogens in monospecies biofilms were exposed to biocides to determine any pathogen-protective effect of the mixed biofilm. Both pathogens and their associate microbial communities were reduced by peracetic acid treatments. S. aureus decreased by 4.6 log cycles in monospecies biofilms, but the pathogen was protected in the five-species biofilm and decreased by only 1.1 log cycles. Sessile cells of L. monocytogenes were affected to the same extent when in a monobiofilm or as a member of the mixed-species biofilm, decreasing by 3 log cycles when exposed to 0.0375% peracetic acid. When the pathogen was exchanged in each associated microbial community, S. aureus was eradicated, while there was no significant effect of the biocide on L. monocytogenes or the mixed community. This indicates that particular members or associations in the community offered the protective effect. Further studies are needed to clarify the mechanisms of biocide protection and to identify the species playing the protective role in microbial communities of biofilms.IMPORTANCE This study demonstrates that foodborne pathogens can be established in mixed-species biofilms and that this can protect them from biocide action. The protection is not due to specific characteristics of the pathogen, here S. aureus and L. monocytogenes, but likely caused by specific members or associations in the mixed-species biofilm. Biocide treatment and resistance are a challenge for many industries, and biocide efficacy should be tested on microorganisms growing in biofilms, preferably mixed systems, mimicking the application environment.
ER -